March 2 (Reuters) - Dominion Energy Inc said on Friday the first vessel carrying liquefied natural gas from its newly constructed Cove Point LNG export terminal in Maryland left the facility, another sign of growing U.S. prowess as an oil and gas producer.

The LNG tanker Gemmata left fully loaded, according to energy data provider Genscape, which said it observed the loading of the vessel through its cameras set up to watch the facility.

Dominion said it spent about $4 billion to add export facilities at Cove Point, long an LNG import terminal on Chesapeake Bay. The facility is still undergoing final commissioning, the company said.

Cove Point is the second big LNG export terminal in the Lower 48 U.S. states after Cheniere Energy Inc’s Sabine Pass terminal in Louisiana, which exported its first cargo in February 2016.

After decades of importing massive amounts of gas, the United States became an exporter of the fuel in 2017 for the first time in 60 years due to record U.S. gas production from shale fields.

The United States is expected to become the world’s third- biggest LNG exporter by capacity in 2018, furthering President Donald Trump’s goal of American energy dominance by exporting U.S. oil and gas to help create jobs at home and provide more security to the nation’s allies around the world.

U.S. LNG export capacity is expected to rise to 10.1 billion cubic feet per day (bcfd) by the end of 2020 from 3.8 bcfd today.

Cove Point is designed to liquefy about 0.75 bcfd of gas. One bcfd can power about 5 million homes.

Dominion said Royal Dutch Shell Plc took the initial LNG cargo from Cove Point. Gemmata is a Shell vessel.

The company did not say where Gemmata was heading. Reuters shipping data said it was available for orders.

Another vessel, the Methane Spirit, is also headed for Cove Point, according to Reuters shipping data. Methane Spirit is located near Singapore and is expected to reach Cove Point around March 31.

Dominion sold the project’s capacity for 20 years to a subsidiary of GAIL (India) Ltd and to ST Cove Point, a joint venture of units of Japanese trading company Sumitomo Corp and Tokyo Gas Co Ltd.

Some of the LNG going to ST Cove Point will go to Tokyo Gas and some will go to Kansai Electric Power Co Inc, according to Sumitomo’s Pacific Summit Energy (PSE) unit.